Many electronic devices are equipped with light-emitting elements. Typically, the housing of such an electronic device has a light-permeable or hollowed-out portion, and a light-emitting element is provided at a position corresponding to the light-permeable or hollowed-out portion, thus allowing the light emitted by the light-emitting element to propagate out of the housing through the light-permeable or hollowed-out portion. In addition to serving as an indicator lamp, the light generated by the light-emitting element may enhance the electronic device esthetically and thereby enrich product design. When designing an electronic device having a plurality of such indicator lamps, the arrangement of the indicator lamps can be changed to produce different visual effects. The shape of each indicator lamp can also be changed to bring about even greater variations visually. For example, the housing of the electronic device can be so designed that each light-permeable or hollowed-out portion has a circular, rectangular, star-like, or annular shape, and that, therefore, when the light-emitting elements respectively corresponding in position to the light-permeable or hollowed-out portions emit light, each indicator lamp is lit in the corresponding circular, rectangular, star-like, or annular shape.
While the aforesaid electronic device can be modified in design by changing the shapes or arrangement of the indicator lamps, not every design can be easily put to practical use with good results. Generally speaking, light-emitting diodes (LEDs), which feature high energy conversion efficiency, long service lives, low susceptibility to damage, a short response time, and high reliability, among other advantages, are perfect for low-luminance applications and are hence widely used as the light source of indicator lamps on electronic devices. However, the light emitted by an LED light source is rather concentrated and can directly and effectively illuminate only a small area. If a light-permeable or hollowed-out portion of the housing of an electronic device is of a shape encompassing a large area (e.g., an annular shape) or of a complicated shape, a single LED light source will be insufficient to provide the desired light-emitting effect, given the light-emitting properties and light-emitting capabilities of LED light sources in general. As a solution, a plurality of light-emitting elements are provided for each indicator lamp, with each light-emitting element corresponding in position to a different part of the corresponding indicator lamp. Nevertheless, not only does this design incur higher production costs, but also uneven light emission may result and thus compromise the intended visual effect. To solve the problem of uneven light emission, a light guide plate may be provided to guide the light emitted by a single light-emitting element to the target area, but this is not a cost-effective solution because light guide plates are typically used in the backlights of screens and are more expensive than most light-emitting elements.
It can be known from the above description that although, in theory, an electronic device can be esthetically improved, and thus effectively enhanced in market competitiveness, by changing the shapes and so on of its indicator lamps, uneven light emission tends to arise when the light-permeable or hollowed-out portions of the housing of the electronic device are of large or complicated shapes. Furthermore, existing solutions to the problem of uneven light emission often lead to a significant increase in production costs and consequently to low market competitiveness. Apparently, the esthetic design of electronic devices has been limited to a large extent by the light-emitting properties, light-emitting effects, and costs of the light sources used. These limiting factors have hindered designers' creativity and prevented an otherwise much greater variety of products from being produced, which is truly a shame. Therefore, the issue to be addressed by the present invention is to design a light guide structure for guiding light broadly, wherein the light guide structure is made of a low-cost light guide material and can guide the light of a single light-emitting element to imitate the broad light-emitting effect of multiple light-emitting elements used together. It is also desirable that the light guide structure enables uniform light emission. The ultimate goal is to allow designers to design electronic devices having various visual effects and hence increased competitiveness without being constrained by costs.